[백준] 1475번_방번호

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		int input = new Scanner(System.in).nextInt();
		result(input);
	}
	
	private static void result(int num) {
		Map<Integer, Integer> map = new HashMap<Integer, Integer>();
		int cnt = 0;
		
		while(num > 0) {
			int digit = num % 10;
			
			if(digit == 6 || digit == 9) {
				cnt++;
			} else {
				if(map.containsKey(digit)) {
					map.put(digit, map.get(digit) +1);
				} else {
					map.put(digit, 1);
				}
			}
			num /= 10;
		}
		map.put(69, (int)Math.ceil(cnt/2.0));
		int max = Collections.max(map.values());
		System.out.println(max);
		
	}
}